Flexible device for conveying powdery granular fibrous or fluid products

ABSTRACT

This invention relates to a flexible device for conveying powdery, granular, fibrous or fluid products, composed of an outer flexible tube having an opening near each of its ends and of a plurality of conveying spirals constituted by helical springs having the same direction of winding, disposed coaxially inside said sleeve and rotated, in the same direction, at speeds which are substantially reverse of their respective pitches.

United States Patent [1 1 Rastoin 1 FLEXIBLE DEVICE FOR CONVEYING POWDERY GRANULAR FIBROUS OR FLU PRODUCTS [76] Inventor: Blaise Rastoin, 42, avenue de la Panouse-Le Cabot, Marseille, France [22] Filed: Jan. 11, 1971 [21] Appl. No.: 105,536

[30] Foreign Application Priority Data Jan. 23, 1970 France ..7002362 [521' US. Cl. ..198/213 51 int. c1 ..B65g 33/00 [58] Field of Search ..198/2l3, 64

[56] References Cited UNITED STATES PATENTS 3,381,801 5/1968 Rastoin 193/213 1 Apr. 10, 1973 FOREIGN PATENTS OR APPLICATIONS 11/1960 Great Britain ..l98/2l3 6/1891 Great Britain ..l98/2l3 Primary Examiner--Evon C. Blunk Assistant Examiner-Douglas D. Watts Attorney-Edwin E. Greigg 1 SCT which are substantially reverse of their respective pitches.

1 Claim, 8 Drawing Figures PATWTED APR 1 0 E973 SHEET 1 BF 2 q rl FLEXIBLE DEVICE FOR CONVEYING POWDERY GRANULAR FIBROUS OR FLUID PRODUCTS The present invention relates to flexible devices for conveying along a possibly winding path which may comprise rising portions, a powdery, granular, fibrous or fluid product, which device is composed of an outer flexible tube having an opening near each of its ends, inside which are disposed a plurality of coaxial conveyer spirals constituted by helical springs, having the same direction of winding, this device being characterized in that said spirals are rotated in the same direction at speeds which are substantially reverse of their respective pitches.

Conveyers are known for powdery or granular products, which are composed of an outer, flexible or non-flexible tube inside which a conveying spiral, constituted by a helical spring, is rotated by one of its ends. These conveyers have a poor yield and several improvements have been made thereto.

One known improvement consists in disposing in the tube a plurality of conveying spirals, wound in contrary direction and rotated in reverse direction from one another. This type of conveyer requires either a plurality of drive motors or an intermediate device between a single motor and the different spirals for converting the rotation of the drive shaft into rotations in the reverse directions.

Another known improvement in conveyers with one spiral consists in disposing, in the center thereof, a cylindrical core which may or may not be flexible. By selecting the diameter of the wire constituting the conveyer spiral and the diameter of the central core so that the conveyer spiral occupies substantially the whole of the space between the. tube and the central core, a dozer conveyer is obtained with regular and proportional output at the speed of rotation of the'spiral.

The present invention relates to improvements which may be applied to all types of existing spiral conveyers.

The improvement according to the invention generally consists in replacing at least one of the spirals of a conveyer of known type by a plurality of spirals having the same direction of winding and driven in the same direction at speeds of rotation which are substantially reverse of their respective pitches. This arrangement has the advantage of reducing the frictions between the various layers of products driven by the concentric spirals. In fact, all the products advance substantially at the same speed as the speed of advance communicated to the products by a spiral is proportional to the product of the pitch by the speed of rotation of the spiral. These products are substantially equal for all the spirals.

In an advantageous embodiment, the different spirals have the same pitch and they are then driven at identical speeds of rotation, this having the advantage of facilitating the drive by a single motor.

A particular case of the preceding case is that where a spiral of a known conveyer is replaced by a plurality of identical concentric spirals, i.e. spirals having the same pitch, disposed about the same imaginary cylinder, so that their loops are alternate. This embodiment enables all the spirals to be rotated simultaneously by fixing them by one of their ends to the same drive shaft.

A conveyer according to the invention comprises at of winding and rotated at speeds that are inversely proportional to their respective pitches. It may also comprise, inside the inner pitch, which has the smallest diameter of winding, a cylindrical flexible core. This rod may be fixed or rotated at the same time as the inner spiral, free to rotate in a bearing or even floating at its two ends.

A conveyer according to the invention may also result from the improvement of a known conveyer composed of two spirals wound in reverse direction and rotating in reverse direction, in which one of the two spirals has been replaced by at least two identical alternate spirals.

The conveyers according to the invention in which a spiral is replaced by at least two identical spirals have a more regular instantaneous output. The amplitude of the variations of instantaneous output due to the pitch of the spiral is attenuated and the instantaneous output approximates to the average output.

It is important to understand that the fact of replacing a spiral by two alternate identical spirals, driven at the same speed, is not equivalent to the fact of replacing a-spiral by another having the same diameter and the same direction of winding and a pitch reduced by 7 half.

In this latter case, the instantaneous output would also be more regular but in order to conserve the same average output, the speed of rotation of the spiral would have to be multiplied by two, the pitch of said spiral having been reduced by half, whilst, according to the invention, the regularity of the output is obtained without having to modify the speed of rotation.

The results and advantages of the invention appear from the following comparative tests.

Table 1 indicates the measurements taken with a conveyer comprising two conveying spirals, having reverse directions of winding, rotated in reverse directions and conveying granulated sugar. The length of the conveyer is 7 meters and it is driven by a 5.5 HP. motor.

Table 2 indicates the measurements taken with the same conveyer in which the outer spiral is replaced by two identical spirals.

TABLE 1 Inlet lntensity Elongation Elongation Output aperture in amperes at starting under load in Kg/h in mm in mm in mm 20 6.5 110 35 1,150 40 7,2 H5 39 2,036 60 7,5 150 47 2,736 80 7,75 175 91 3,800 100 8,5 185 110 4,360 I20 9,5 195 l25 4,510

TABLE 2 Inlet aperture intensity Elongation Elongation Output in mm in amperes at starting under load in lCg/h in mm in mm These tests'show that, in a conveyer according to the invention, the elongation of the spirals at starting and under load is much reduced. This property brings about a very important practical consequence it enables a much longer conveyer to be constructed.

With equal output, the conveyers according to the invention enable much larger dimensions to be adopted for the inlet opening for the products. This property enables a more precise regulation of the output to be obtained by adjusting the inlet aperture, especially for the small outputs where the variations become less rapid.

A characteristic property of a conveyer with helical spirals is its speed of equilibrium, i.e., the speed of rotation of the spiral for which the conveyed product remains in equilibrium in a rising portion of the conveyer. In the conveyers according to the invention, this speed of equilibrium is smaller than in the known conveyers, this enabling lower speeds of rotation of the spirals to be adopted.

As the elongation of the spirals is more reduced and the intensity absorbed for the same inlet opening for the products is lower, the conveyer according to the in vention enable starting to be effected under a greater load with respect to the maximum output.

The invention will be more readily understood with reference to the accompanying drawings, in which:

FIG. 1 is a view of the whole of a conveyer according to the invention.

FIGS. 2, 3, 4 and show, on a larger scale, sections of conveyer according to the invention.

FIG. 6 is a transverse section through VIVI of FIG. 5.

FIG. 7 represents the fixation of two spirals on the drive shaft.

FIG. 8 shows a conveyer with two spirals wound in reverse direction, the outer spiral of which is doubled.

Referring now to the drawings, FIG. 1 shows a hopper 1 containing a powdered product, a hopper 2 and a conveyer 3 transporting the product from hopper l to hopper 2 along a possibly winding path which may comprise rising parts. The conveyer 3 is a flexible conveyer comprising an outer flexible tube 4 having an inlet opening 5 for the products and an outlet opening 6 for the products near its ends. The opening 5 is connected to the mouth of the outlet spout 7 of the hopper l. A sliding obturator 8, placed on this outlet spout, enables the opening thereof to be adjusted and the output of the conveyer 3 to be controlled. The opening 6 is located above the hopper 2 into which the products fall by gravity. Inside the tube 4 are placed two helically wound wires 9 and 10. Said latter are wound in the same direction, their pitch is identical and their diameter of winding is identical. They are fixed by their lower ends to the periphery of a shaft end 11 rotated by a motor 12. A cylindrical core 13 is placed inside the two spirals 9 and 10. This core 13 is for example fixed to the center of the tube, at one of its ends, by the support 14 whilst the other end is free. The support 14 may also be a bearing in which the core 13 may rotate freely. The core 13 may also, as a variant, be rotated at the same time as the spirals. It may also be floating, i.e., its two ends may be free.

The conveyer as has just been described may comprise numerous solutions. The motor 12 may be placed at the downstream end instead of being placed at the upstream end as in the Figure.

The characteristic of the invention resides in the fact that the conveyer comprises a plurality of conveying spirals 9 and 10, wound in the same direction and rotated in the same direction at speeds which are reversely proportional to their respective pitches. The direction of rotation of the spirals determines the direction of advance of the products, the conveyer being reversible.

The conveyer shown in FIG. 1 is composed of two identical spirals 9 and 10 rotated simultaneously by the same motor. This mode of execution facilitates the drive of the two spirals by means of a single motor. The spirals may obviously be multiplied without being limited to two. However, this embodiment presents a difficulty if the spirals are made separately, as they must then be screwed in one another from one end. This difficulty is avoided if the spirals are made simultaneously by winding a plurality of wires on the same mandrel.

FIGS. 2, 3 and 4 show, on a larger scale, sections of conveyers according to the invention.

The conveyer of FIG. 2 is composed of an outer tube 15 and two spirals constituted by wires 16 and 17 wound along concentric helices. The direction of winding of the two helices is the same. The diameter of winding of the wire 16 is larger than that of the wire 17. On the other hand, the pitch of the helix 17 is greater than that of helix 16. The two spirals are rotated in the same direction as indicated by arrow 18 and the products are then driven in the direction of arrow 19. The speed of rotation of the spiral 17, which has the larger pitch, is lower than the speed of rotation of the spiral 16, so that the product of the speed by the pitch, which is in direct relation with the speed of displacement of the products, is equal for the two spirals.

The conveyer of FIG. 3 comprises two spirals 20 and 21, which are always wound in the same direction. The outer spiral 20 has a larger diameter of winding than the spiral 21. On the contrary, the pitches of the two spirals are substantially equal and the two spirals are rotated in the same direction and at the same speed. If they are driven in the direction shown by arrow 22, the products advance in the direction of arrow 23.

FIG. 4 shows on a larger scale a section of conveyer which is an improvement of a conveyer with one spiral 24 with an inner cylindrical core 25. The improvement according to the invention consists in doubling the single spiral 24 by a second identical spiral 26. When the two spirals are rotated at the same time in the direction of arrow 27, the products advance in the direction of arrow 28. More than two spirals may also be provided.

FIGS. 5 and 6 show a section of a dozer conveyer according to the invention, which is an improvement in a known doser conveyer with a single spiral 29. According to the invention, the spiral 29 is doubled by a second identical spiral 30. The cylindrical core 31 is constituted by a tube whose outer diameter is slightly less than the diameter of winding of the spirals 29 and 30, while the diameter of the wire which constitutes the spirals 29 and 30 is slightly smaller than the difference between the radius of the tube 32 and the radius of the central core 31. In such a conveyer, the average output is determined by the speed of rotation of the spirals and this output may be dosed by varying the common speed of drive of the spirals. More than two identical alternate spirals may obviously be provided.

FIG. 7 shows a mode of fixing the end of two identi- 4 cal spirals 33a and 33b to a common drive shaft 34. The end of each spiral is engaged in a bore 35a and 35b bored in the head of a bolt 36a and 36b. The two bolts pass through the shaft 34 and are held in clamped position by nuts 37a and 37b. In the locked position, the heads of the bolts are engaged in a bore hollowed out in the drive shaft so that the wire of the spirals is securely 1. In a conveying device for pulverulent, granular, fibrous or fluid substances having an outer flexible tube with two ends; first'means defining an inlet opening in said tube adjacent one end thereof; second means defining an outlet opening in said tube adjacent the other end thereof; spiral means rotated inside said tube for feeding said substance through said tube from said inlet opening to said outlet opening and a flexible core disposed axially inside said spiral means, said conveying device further characterized in that said spiral means comprises two identical, interlaced, coaxial helical wires wound in the same direction around the flexible core and arranged to be rotated simultaneously at equal speeds by a single shaft, said core and said helical wires having a cross section which substantially occupies the whole of the interior of said outer flexible tube with the flexing of the flexible core and the surrounding tube maintaining the helical wires in proper relation for transporting substances and said helical wires further being free of any driving relation with the core. 

1. In a conveying device for pulverulent, granular, fibrous or fluid substances having an outer flexible tube with two ends; first means defining an inlet opening in said tube adjacent one end thereof; second means defining an outlet opening in said tube adjacent the other end thereof; spiral means rotated inside said tube for feeding said substance through said tube from said inlet opening to said outlet opening and a flexible core disposed axially inside said spiral means, said conveying device further characterized in that said spiral means comprises two identical, interlaced, coaxial helical wires wound in the same direction around the flexible core and arranged to bE rotated simultaneously at equal speeds by a single shaft, said core and said helical wires having a cross section which substantially occupies the whole of the interior of said outer flexible tube with the flexing of the flexible core and the surrounding tube maintaining the helical wires in proper relation for transporting substances and said helical wires further being free of any driving relation with the core. 